Diltiazem and Simvastatin interaction
Diltiazem and Simvastatin: both prescribing labels flag this combination with the strongest language, such as a contraindication, a boxed warning, or an instruction to avoid it.
Do not combine without a prescriber's guidance. The label language below is the strongest FDA uses.
What the FDA labels say
From the Diltiazem (DILTIAZEM HYDROCHLORIDE in SODIUM CHLORIDE) label · effective 2025-04-15
• Statins: Avoid statins metabolized by CYP3A4.
Limit daily dose of simvastatin to 10 mg and diltiazem to 240 mg [see Clinical Pharmacology (12.3)].
Statins Increased risk of myopathy and rhabdomyolysis with statins metabolized by CYP3A4.
When possible, use a non-CYP3A4-metabolized statin with diltiazem.
From the Simvastatin (ZOCOR) label · effective 2025-03-28
ZOCOR is contraindicated in the following conditions: Concomitant use of strong CYP3A4 inhibitors (select azole anti-fungals, macrolide antibiotics, anti-viral medications, and nefazodone) [see Drug Interactions (7.1) ] .
Concomitant use of strong CYP3A4 inhibitors (select azole anti-fungals, macrolide antibiotics, anti-viral medications, and nefazodone) ( 4 , 7.1 )
Steps to Prevent or Reduce the Risk of Myopathy and Rhabdomyolysis The concomitant use of strong CYP3A4 inhibitors with ZOCOR is contraindicated.
Intervention: Concomitant use of strong CYP3A4 inhibitors with ZOCOR is contraindicated [see Contraindications (4) ] .
If treatment with a CYP3A4 inhibitor is unavoidable, suspend ZOCOR during the course of strong CYP3A4 inhibitor treatment.
Taking more than these two? Interactions stack. Check your whole list at once; it stays in your browser.
Open in the checkerNot medical advice. Interaction Checker quotes FDA label text and NIH fact sheets. Whether an interaction matters for you depends on doses, timing, kidney and liver function, and other conditions. Confirm with a pharmacist or prescriber.